It is desirable to utilize an electrical winch for taking up many different loads. Winches are particularly desirable for pulling boats out of the water, for example onto a trailer, and for letting a boat off of a trailer into the water. It is desirable that such winches be powered by a twelve volt battery, which typically will be associated with the vehicle pulling the trailer, and the winches must be also capable of manual operation, and must assist in positively preventing the load (boat) from moving off of the trailer once the cable connected to the load is taken up.
According to the present invention a winch assembly is provided which is useful for many different purposes, but is particularly useful in association with boat trailers. The winch has a reversible electric motor which is readily powered to take up the cable, but is braked by an advantageous braking mechanism in a manner that positively prevents the cable from playing out once the load has been taken up. However when it is desired to let out the cable electrically, simply by moving the switch actuator for energizing the motor the braking mechanism is deactivated, allowing control of let-off of the cable connected to the load (boat). The cable can also be taken up manually without having to disconnect the motor from the drive mechanism for taking up the winch drum, and when there is no load on the cable and it is desired to let the drum "free wheel" to facilitate connecting of the cable to the load, a clutch may be deactivated by a readily accessible knob.
According to one aspect of the present invention a winch assembly is provided comprising the following elements: A drum rotatable about a first axis adapted to be connected by a cable to a load. A reversible electric motor having an output shaft. Means for power rotating the drum mounted on a drum shaft about the first axis either clockwise or counter clockwise in response to power supplied from the motor, including an electrical switch for connecting the motor to a source of electrical power. The switch includes an actuator and having off, forward, and reverse positions corresponding to an off condition, and forward and reverse rotation directions, respectively, of the output shaft. Braking means for braking the motor output shaft to prevent movement thereof at least in the reverse direction when the switch is in the off position. And, means for mechanically deactivating the braking means when the switch is in the reverse position, the means comprising an extension of the switch actuator.
The power rotating means may comprise: A first sprocket connected to the motor output shaft, a second sprocket which spins on the drum shaft, and a chain extending between the sprockets; a first gear connected to and rotatable with the second sprocket; a drive gear meshing with the first gear and mounted on a second shaft; a second gear mounted on the second shaft; an idler gear meshing with the second gear and mounted on an idler shaft; a third gear mounted on the idler shaft; and a fourth gear rigidly connected to the drum, and meshed with the third gear so that the motor drives the drum through (in sequence) the first sprocket, chain, second sprocket, first gear, drive gear, second gear, idler gear, third gear and fourth gear.
The braking means comprises a brake arm with a brake lining engageable with a brake hub of a one way bearing assembly on the output shaft which, when braked by the brake arm and lining, allows forward rotation of the output shaft but not reverse rotation thereof; and a spring biasing the brake lining into engagement with the one way bearing assembly hub.
The brake arm is stationarily mounted at a first end thereof on a first side of the one way bearing assembly, and a second end thereof is engageable by the switch actuator and is on a second side of the one way bearing assembly opposite the first side. The brake spring (e.g. a coil tension spring) engages the brake arm adjacent the second end thereof, and the brake lining engages the one way bearing assembly over an arc of more than 90.degree..
The means for power rotating the drum may also include a clutch, and means for manually deactivating the clutch so that the drum may free-wheel, not being operatively connected to the motor output shaft. Further, there preferably also is provided means for manually rotating the drum about the first axis independent of the motor in the forward rotation direction to wind up a cable thereon to pull a load.
It is the primary object of the present invention to provide a simple yet effective winch assembly, particularly useful for marine applications, which has positive braking action and good versatility. This and other objects of the invention will become clear from an inspection of the detailed description of the invention, and from the appended claims.